Welding electrode

ABSTRACT

This invention comprises a coated electrode having a core of copper or a copper alloy and aluminum or an aluminum alloy. The coating of the electrode is composed of the fluoride of at least one of the metals chosen from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium, and the chloride of at least one of the metals chosen from the same group.

United States Patent A. David Joaph New Canaan, Conn. 770,787

Oct. 25, 1968 Nov. 16, 1971 Eutectic Corporation Flushing, N.Y.

[ 72] Inventor [21 Appl. No. [22] Filed [45] Patented [73] Assignee [54] WELDING ELECTRODE 10 Claims, No Drawings [52] US. Cl 219/146, 1 17/202, 1 17/206, 148/26 51 Int. Cl 823k 35/22 [50] Field of Search 117/202,

[56] References Cited UNITED STATES PATENTS 1,115,317 10/1914 Kjellberg 117/206 1,763,417 6/ 1930 Clark 1 17/202 2,632,080 3/1953 Wassennan 1 17/206 Primary Examiner-William L. Jarvis Attorney-Gladstone 1'1. Kapralos WELDING ELECTRODE It is the general object of the present invention to provide an aluminum electrode that would be capable of depositing a weld deposit on an aluminum base metal wherein said weld deposit has a greater hardness than the aluminum base metal.

Another object of the present invention is to provide an aluminum electrode that would weld deposit on aluminum base metal with minimum fusion (melting) of the base metal.

Other objects and advantages will also be observed as the description of this invention proceeds.

The novel electrode is a coated electrode having a core which consists principally of aluminum and copper. The aluminum can be either pure aluminum (with impurities) or an aluminum alloy such as for example an aluminum alloy with up to 13 percent by weight silicon. The copper can be either pure copper or one of the well-known copper alloys such as those alloys known as brasses, bronzes or nickel silvers.

The core can be a copper or copper alloy tube with aluminum or an aluminum alloy filler inside the tube or conversely an aluminum or aluminum alloy tube with a copper or copper alloy filler in the tube. The tube filler can be of any suitable form such as a solid rod, another tube, a number of wires or powder.

It has been found that the core must have from 2 to 30 percent by volume of copper or copper alloy with 5 to percent by volume of copper or copper alloy being preferred.

As is understood by those skilled in the art, the copper or copper alloys and aluminum or aluminum alloys contain the minor impurities usually found in these metals.

The flux coating is made to contain one or more fluorides and one or more chlorides, the fluoride content consisting of the fluoride of one or more of the metals of the group which consists of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium, and the chloride content consisting of the chloride of one or more of the metals of the same group.

It is important that the coating include not less than 15 percent flouride and not less than 55 chloride; the ranges; therefore, being fluoride content 15 to 45 percent and chloride content 55 to 85 percent.

A typical example of a rod composition which has been found to yield very satisfactory results is; a core comprising a copper tube filled with a rod of an aluminum alloy having aluminum 85 percent, silicon 15 percent, coated with a flux compound as follows: fluoride 30 percent; chloride 70 percent.

The electrode of the present invention has been found to be lower melting than aluminum and therefore can be weld deposited on aluminum without excessive fusion (melting) of the aluminum base metal. In addition, the weld deposit of the present invention is much more dense (porosity free) as contrasted by the weld deposits of known aluminum electrodes.

The most important asset of the present invention is the fact that the welding electrode deposits a weld deposit having a hardness in the range of Rockwell B (scale) 50. This hardness is much higher than the hardness of pure aluminum or the widely used aluminum-silicon alloys which means that the present electrode can be used as an aluminum hardfacing electrode. Heretofore no aluminum hardfacing electrode has been known.

Additionally, the present electrode has good weldability and excellent surface-wetting characteristics.

The foregoing specification describes the more desirable embodiments of the invention. It is to be understood that the teachings of this invention encompasses other similar embodiments which should be considered as encompassed within the spirit of the invention as defined in the claims.

I claim:

1. A coated electrode having a core comprising copper or a copper alloy and aluminum or an aluminum alloy wherein the copper or the copper alloy comprises from 2 to 30 percent by volume of the core and a coating composed of the fluoride of at least one of the metals chosen from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium; and the chloride of at least one of the metals chosen from the same oup.

2. The electrode 0 claim 1 wherein said fluoride content constituting 15 to 45 percent of the coating, and the chloride content constituting the remainder.

3. The electrode of claim 1 wherein said copper alloy is pure copper.

4. The electrode of claim 1 wherein said aluminum alloy is pure aluminum.

5. The electrode having a core comprising a tube of copper or copper alloy and a filler metal of aluminum or an aluminum alloy inside said tube said core having a coating composed of the fluoride of at least one of the metals chosen from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium; and the chloride of at least one of the metals chosen from the same group.

6. The electrode having a core comprising a tube of aluminum 'or an aluminum alloy and a filler metal of copper or a copper alloy inside said tube said core having a coating composed of the fluoride of at least one of the metals chosen from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium; and the chloride of at least one of the metals chosen from the same group.

7. The electrode of claim 5 wherein said core comprises 2 to 30 percent by volume of copper or a copper base alloy.

8. The electrode of claim 7 wherein said core comprises 5 to 20 percent by volume of copper or a copper base alloy.

9. The electrode of claim 6 wherein said core comprises 2 to 30 percent by volume of copper or a copper base alloy.

10. A coated electrode of claim 1 comprising:

A. a core comprising:

1. a copper tube filled with 2. an aluminum alloy having percent aluminum, 15

percent silicon B. a coating on the core, the coating comprising:

1. 30 percent of a fluoride selected from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium; and

2. 70 percent of chloride selected from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium.

I II I I i 

2. The electrode of claim 1 wherein said fluoride content constituting 15 to 45 percent of the coating, and the chloride content constituting the remainder.
 2. an aluminum alloy having 85 percent aluminum, 15 percent silicon B. a coating on the core, the coating comprising:
 2. 70 percent of chloride selected from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium.
 3. The electrode of claim 1 wherein said copper alloy is pure copper.
 4. The electrode of claim 1 wherein said aluminum alloy is pure aluminum.
 5. The electrode having a core comprising a tube of copper or copper alloy and a filler metal of aluminum or an aluminum alloy inside said tube said core having a coating composed of the fluoride of at least one of the metals chosen from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium; and the chloride of at least one of the metals chosen from the same group.
 6. The electrode having a core comprising a tube of aluminum or an aluminum alloy and a filler metal of copper or a copper alloy inside said tube said core having a coating composed of the fluoride of at least one of the metals chosen from the group consisting of aluminum, sodium, lithium, potassium, barium, calcium, zinc, tin and cadmium; and the chloride of at least one of the metals chosen from the same group.
 7. The electrode of claim 5 wherein said core comprises 2 to 30 percent by volume of copper or a copper base alloy.
 8. The electrode of claim 7 wherein said core comprises 5 to 20 percent by volume of copper or a copper base alloy.
 9. The electrode of claim 6 wherein said core comprises 2 to 30 percent by volume of copper or a copper base alloy.
 10. A coated electrode of claim 1 comprising: A. a core comprising: 